In this task, you're given a passage, further information available on a particular linked term from the statement, and a question. Your job is to generate the answer to the question by using the information provided. If there is no clear answer obtainable, output 'none'.

Passage: As designed in 1931, the He 46 was a two-seat sesquiplane of mixed construction. The upper wing was swept back 10°. This is a common trick when a change in an aircraft's design moves the center of gravity to the rear; rather than moving the whole wing back to counter for the shift, it is easier to simply angle the wings back slightly, which requires very little change to the basic design, or even the overall structure of the wing. (The similarly angled wings on the Fairey Swordfish are due to just such a mid-program change to the weight distribution of the aircraft.) The tailplane was mounted high and braced by struts. The undercarriage was fixed, and the tail was fitted with a skid rather than a wheel. The He 46 prototype first flew in late 1931; its flight characteristics were good, but design improvements were incorporated. The small lower wing was removed, while the mainplane was increased in area by 22% and braced to the fuselage, transforming the He 46 into a parasol-wing monoplane. A more powerful engine was added to the second prototype, and a single 7.92 mm (.312 in) MG 15 machine gun for the rear seat was added to the third prototype.
 Link Information: he World War II MG 15 was used in nearly all Luftwaffe aircraft with a flexible-mount defensive position. Question: What other planes were fitted with the MG 15?
Answer: nearly all Luftwaffe aircraft with a flexible-mount defensive position

Passage: Chibnall suggested including a "bonkers" gang of characters picked from around time and space. He felt that Doctor Who could have "collisions of characters that no other show in the world can do", and that it was about finding a "disparate" group of characters who would "bounce" off each other. Nefertiti's decision not to return to her own time fits in with the historical record, as the date and cause of her death are unknown. Chibnall asked to introduce Rory's father, as Amy and Rory would be leaving in four episodes and Rory's family life had not been explored yet. Mark Williams who played Rory's father previously appeared in the Fifth Doctor audio adventure The Eternal Summer. Rupert Graves, who played an Edwardian hunter in this episode, previously worked with Moffat on the BBC series Sherlock. David Bradley's character, Solomon, was modelled on a "well-known nightclub owner with long hair". Chibnall described him as "half businessman, half Somali pirate". Bradley and Williams had previously worked together on the Harry Potter film franchise. Bradley was later cast as the First Doctor William Hartnell for the 50th anniversary documentary drama An Adventure in Space and Time. Comedy duo Mitchell and Webb provided the voices of Solomon's two robots; executive producer Caroline Skinner called the casting choice "perfect". Richard Hope, who played the Silurian Bleytal, previously appeared as Malohkeh in the episodes "The Hungry Earth", "Cold Blood" and "The Wedding of River Song".
 Link Information: An Adventure in Space and Time is a 2013 British biographical television film Question: What year did the 50th anniversary documentary come out?
Answer: 2013

Passage: The Bougainville invasion was the ultimate responsibility of Admiral William F. Halsey, commander South Pacific Area, at his headquarters at Nouméa, New Caledonia. The landings were under the personal direction of Rear Admiral Theodore S. Wilkinson, commander III Amphibious Force, aboard his flagship, attack transport . Also aboard was Lieutenant General Alexander A. Vandegrift, commander I Marine Amphibious Corps. Loaded aboard eight attack transports (APAs) and four attack cargo transports (AKAs), organized into three transport divisions, were the men of the 3rd Marine Division (reinforced), Major General Allen H. Turnage commanding. The fighting on Bougainville would be the division's first action of the war. With Turnage aboard the was Commodore Lawrence F. Reifsnider, who had responsibility for the transports and attack cargo ships. The transport divisions were escorted by a screen consisting of 11 destroyers, and were supported by various fleet tugs, minesweepers and minelayers. Anti-aircraft guns from the 3rd Marine Defense Battalion under Lieutenant Colonel Edward H. Forney and several field artillery batteries from the 12th Marine Regiment under Colonel John B. Wilson were assigned to the operation to provide support to ground troops once ashore. Direct air cover for the landing was provided by Major General Nathan Twining's AirSols command, which included aircraft from: the US Army Air Force (USAAF) the United States Navy the United States Marine Corps and the Royal New Zealand Air Force (RNZAF). Lieutenant General George Kenney's Fifth Air Force was also tasked with supporting operations around Bougainville by conducting raids on Japanese air and naval assets around Rabaul.
 Link Information: .

A total of 388 APA (troop) Question: How many AKAs in total were built for service?

Answer: 388

